1. Field of the Invention
The present invention relates to an ink set to be used for an ink-jet recording method and a method for producing a tetra-composite black image.
2. Description of the Related Art
In ink-jet recording, an achromatic image is formed with a black ink or a combination of yellow, cyan and magenta inks. However, when a dye is used as the coloring agent of each ink, a problem arises that the achromatic image is tinted as fading proceeds. Hence, in order to prevent achromatic image from being tinted during long term storage so that the achromatic color is maintained, a black ink has been proposed which is prepared by using a water-soluble black dye having a specific structure in combination with C.I. Direct Red 89.
When achromatic area in an image is formed with a single black ink, the area may be grainy when the achromatic color is light color. In some cases, in order to eliminate the graininess, such an achromatic area is formed with a combination of black, yellow, magenta and cyan inks. Furthermore, when an image such as photograph is printed, an achromatic area is generally formed with a combination of black, yellow, magenta and cyan inks. With such a printing method, high printing quality, including high-definition and high gradation, may be achieved. However, when the color of an image including an achromatic area fade, the achromatic area may be noticeably tinted, and therefore the image could look unnatural.